package com.szly.phm.common.utils; /**
 * 引进的包都是Java自带的jar包
 * 秘钥相关包
 * base64 编解码
 * 这里只用到了编码
 */

import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;
import java.util.Base64.Encoder;
import java.util.HashMap;
import java.util.Map;

import static cn.hutool.core.convert.Convert.toStr;

public class RSAKeyUtils {

    public static final String KEY_ALGORITHM = "RSA";
    //public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    //获得公钥
    public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
        //获得map中的公钥对象 转为key对象
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        //byte[] publicKey = key.getEncoded();
        //编码返回字符串
        return encryptBASE64(key.getEncoded());
    }

    //获得私钥
    public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
        //获得map中的私钥对象 转为key对象
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        //byte[] privateKey = key.getEncoded();
        //编码返回字符串
        return encryptBASE64(key.getEncoded());
    }

    //解码返回byte
    public static byte[] decryptBASE64(String key) throws Exception {
        return (Base64.getDecoder()).decode(key);
    }

    //编码返回字符串
    public static String encryptBASE64(byte[] key) throws Exception {
        Encoder encoder = Base64.getEncoder();
        String encode = encoder.encodeToString(key);
        return encode;
    }

    //map对象中存放公私钥
    public static Map<String, Object> initKey() throws Exception {
        //获得对象 KeyPairGenerator 参数 RSA 1024个字节
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        //通过对象 KeyPairGenerator 获取对象KeyPair
        KeyPair keyPair = keyPairGen.generateKeyPair();

        //通过对象 KeyPair 获取RSA公私钥对象RSAPublicKey RSAPrivateKey
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        //公私钥对象存入map中
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    //String转换公钥
    public static RSAPublicKey toPubkey(String pubKey) {
        RSAPublicKey publicKey = null;
        try {
            byte[] keyBytes;
            keyBytes = (Base64.getMimeDecoder()).decode(pubKey);
            X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            publicKey = (RSAPublicKey)keyFactory.generatePublic(keySpec);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        }
        return publicKey;
    }

    //string转秘钥
    public static RSAPrivateKey toPrikey(String prikey) {
        RSAPrivateKey privateKey = null;
        PKCS8EncodedKeySpec priPKCS8;
        try {
            //String prikey = toStr(path);
            priPKCS8 = new PKCS8EncodedKeySpec(Base64.getMimeDecoder().decode(prikey));
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            privateKey = (RSAPrivateKey) keyf.generatePrivate(priPKCS8);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeySpecException e) {
            e.printStackTrace();
        }
        return privateKey;
    }


    public static void main(String[] args) {
        Map<String, Object> keyMap;
        try {
            keyMap = initKey();
            String publicKey = getPublicKey(keyMap);
            System.out.println("公钥");
            System.out.println(publicKey);
            String privateKey = getPrivateKey(keyMap);
            System.out.println("私钥");
            System.out.println(privateKey);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


}